Process for the preparation of an organomercaptophenol from sulfur, a 2,6-disubstituted phenol, and an activated olefin or an epoxy compound

ABSTRACT

A process for the preparation of an organomercaptophenol is described which comprises the reaction of sulfur with a 2,6-disubstituted phenol carried out in the presence of (1) a base, (2) an activated olefin or an epoxy compound, (3) and a solvent with a high dielectric constant. The organomercaptophenols produced by this process are useful as monomers in the synthesis of esters, carbonates, ethers, epoxy compounds, among many other chemicals synthesized from monohydric phenols. In addition, the organomercaptophenols are also useful as antioxidants.

This is a division of application Ser. No. 484,996, filed July 1, 1974, now U.S. Pat. No. 3,979,460, issued Sept. 7, 1976.

This invention relates to a process for the preparation of an organomercaptophenol under reaction conditions which comprise contacting sulfur and a 2,6-disubstituted phenol in the presence of (1) a base, (2) an activated olefin or an epoxy compound, (3) and a solvent with a high dielectric constant.

Various observations have been made by the prior art regarding reactions between phenolic reactants and sulfur carried out in the presence of a base, such as those described in:

I A. J. Neale's description of the preparation of monothiobisphenols and oligomeric phenols by the reaction of phenol and sulfur at temperatures of 140°-180° C. during time periods of 6 to 24 hours (Tetrahedron, Vol. 25, Pergamon Press (1969), Printed in Great Britain, pages 4593 to 4597);

II E. J. Geering's description of the preparation of a phenol-sulfide having an average of at least two sulfur atoms per linkage by the reaction sulfur and a phenolic reactant having at least one ortho position substituted by hydrogen at temperatures of 100°-200° C. during time periods of 1/2 to 15 hours (A. J. Geering et al., U.S. Pat. No. 3,647,885);

III T. Fujisawa's description of the preparation of 4-arylthio-2,6-dialkylphenols by the reaction of 2,6-dialkylphenols and aromatic disulfides carried out at elevated temperatures during time periods of 1/2 to 50 hours in the presence of a solvent (Fujisawa et al., U.S. Pat. No. 3,697,601, further described by Fujisawa in the article Sulfenylation of Hindered Phenols With Aryl Disulfides, J. Org. Chem., Vol. 38, No. 4 (1973) pages 687-690);

IV T. Fujisawa, K. Hata, and T. Kojima's description of the preparation of thiobis-2,6-dialkylphenols and polythiobis-2,6-dialkylphenols by the reaction of 2,6-disubstituted sterically hindered phenols with sulfur in an alcohol at room temperatures to 100° C. during time periods of 1/2 to 1 hour (Synthesis, Vol. 1, January 1973, pages 38-39).

Other prior art publications, among others, which related to the reaction of phenol and sulfur which illustrate the state of the art are the following:

E. J. Geering et al., U.S. Pat. No. 3,717,682 and 3,743,680, as well as Rearrangements and Decompositions of Thiobisphenols by A. J. Neale et al., Tetrahedron, Vol. 25, Pergamon Press (1969) Printed in Great Britain, pages 4593-4597.

Essentially, this invention embodies a process for the preparation of an organomercaptophenol which comprises contacting sulfur and a 2,6-disubstituted phenol carried out in the presence of (1) a base, (2) an activated olefin or an epoxy compound, (3) and a high dielectric constant solvent.

The process of preparing an organomercaptophenol comprises the reaction of any 2,6-disubstituted phenol having a hydrogen atom in the para position relative to the position of the hydroxyl group of the phenol subject to the proviso that any other substituents do not interfere with the formation of an organomercaptophenol in accordance with the reaction parameters of this invention. Among others, phenols suited to the practice of this invention can be described by the following structural formula: ##STR1## wherein independently each R¹ and R² is a monovalent substituent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, and each R³ and R⁴ is a monovalent substituent selected from the group consisting of hydrogen, hydrocarbon and hydrocarbonoxy radicals. Preferably the hydrocarbon and hydrocarbonoxy radicals have from 1 to 30, more preferably from 1 to 15, and even more preferably from 1 to 6 carbon atoms. Representative of phenols of Formula I., among others, which can be employed are as follows:

2,6-dimethylphenol,

2,6-diethylphenol,

the 2,6-dipropylphenols (2,6-di-n-propyl and 2,6-di-sec-propylphenol),

the 2,6-dibutylphenols (2,6-di-n-butyl, 2,6-di-sec-butyl, 2-cyclohexylphenol, and 2,6-di-tertbutylphenol),

2,6-dicyclohexylphenol,

the 2,6-dioctylphenols,

the 2,6-didodecylphenols,

the 2,6-ditridecylphenols,

the 2,6-ditetradecylphenols,

the 2,6-dioctadecylphenols,

the 2,6-didocosylphenols,

the 2,6-dihexacosylphenols,

the 2,6-ditriacontylphenols,

2,6-diphenylphenol,

2,6-dibenzylphenol,

the 2,6-ditolylphenols,

the 2,6-dinaphthylphenols,

2,6-dimethoxyphenol,

2,6-diethoxyphenol,

2,6-dibutoxyphenol,

2,6-dilauroxyphenol,

2,6-diphenoxyphenol,

2-methyl-6-tert-butylphenol,

2,3,5,6-tetramethylphenol,

the 2-propyl-6-phenylphenols, etc.

The hydrocarbon and hydrocarbonoxy substituents of Formula I can be the same or different and can be selected from the group consisting of alkyl, cycloalkyl, aryl, alkoxy, cycloalkoxy, aryloxy, and combinations thereof. A preferred phenol reactant class within the practice of this invention are the phenols having R¹ and R² substituents selected from the lower alkyl group consisting of C₁₋₂ radicals, wherein the R³ and R⁴ substituents are hydrogen. Particularly preferred is 2,6-dimethylphenol, also known as 2,6-xylenol.

My process employs sulfur in any of its elemental forms or as polysulfide ions represented by the generic formula M_(y) S_(x) wherein x is a positive integer at least equal to 2 and wherein M is selected from the group consisting of alkali and alkaline earth metals as well as ammonium ions R₄ N⁺ where R is hydrogen or a hydrocarbon. Preferably elemental sulfur is employed. Because of its economic advantage, elemental sulfur can be employed in any of the commonly known commercial forms, such as bright sulfur (99.5%) dark sulfur (up to 1% carbonaceous material); refined sulfur (99.8%); high purity sulfur (99.97%); sublimed sulfur (flowers of sulfur); flour sulfur, ground refined or crude sulfur in various mesh sizes; and Rubbermakers, a ground special grade.

Any base that can be employed which will dissolve in the phenol reaction mixture and form a metal phenoxide (sometimes referred to as a metal phenolate or phenates). Representative among others, of basic species which can be employed are elemental alkali and alkaline earth metals; ammonium alkali or alkaline earth metal hydroxides; salts of strong bases and weak organic acids; etc. Specific examples include sodium, potassium, and magnesium metal; ammonium sodium, potassium, lithium, and calcium hydroxide; ammonium sodium, lithium, and barium carbonates, sodium acetate, sodium benzoate, sodium methylate, sodium thiosulfate, sodium sulfide, sodium tetrasulfide, sodium cyanate, etc. Preferred basic species are the metals sodium and potassium, sodium and potassium hydroxides and salts of sodium and potassium bases and weak organic acids.

In accordance with the process of this invention, in addition to the phenol, sulfur and base, the process is carried out in the presence of a promoter which shifts the equilibrium point of the reaction in favor of the formation of the organomercaptophenol. These promoters are selected from the class consisting of activated olefins and epoxy compounds. Among others, activated olefin compounds may be represented by the Formula II set out hereafter: ##STR2## wherein independently at least one of the R_(a), R_(b), R_(c) and R_(d) substituents is selected from the electron-attracting group consisting of cyano, i.e. --CN; carbamoyl, i.e. --CON(R')₂ ; oxycarbonyl, i.e. --COOR"; oxohydrocarbyl, i.e. --COR", radicals; wherein independently each R' represents hydrogen, acyclic and cyclic hydrocarbon radicals, independently R" represents acyclic and cyclic hydrocarbon radicals.

Preferably the activated olefins have from 3 to 10 carbon atoms, more preferably from 3 to 5 carbon atoms. The olefins may be either mono- or polyolefinic and may be either conjugated or nonconjugated in unsaturation. Among others, representative of activated olefin species are such compounds as acrylamide, α-methylacrylamide, N-methylacrylamide, N-phenylacrylamide, N,N-diisobutylacrylamide, acrylonitrile, α-phenylacrylonitrile, vinyl chloride, vinylidene chloride, vinyl methyl ether, vinyl ethyl ether, vinyl n-propyl ether, vinyl n-octyl ether, vinyl n-octadecyl ether, vinylidenecyanide, sometimes referred to as methylene malonotrile, vinyl succinimide, N-vinyl N-methylacetamide, N-vinyl N-phenylacetamide, N-vinyl diglycolylimide, etc. Preferred olefins are monoolefinic C₃ -C₅ carbonitrides, such as acrylonitrile, α-methyl acrylonitrile, α-ethyl acrylonitrile, butyronitrile and α-methylbutyronitrile.

Among others, epoxy compounds can be represented by the Formula III set out hereafter: ##STR3## wherein independently each R_(e) and R_(f) substituents are selected from the group consisting of hydrogen, acyclic and cyclic radicals. Preferably, the R_(e) and R_(f) radicals are free of any electron-attracting substituents which can substantially reduce the ease of carbon-oxygen bond breakage. Preferred epoxy compounds are epoxides containing from 2 to 10 carbon atoms, more preferably from 2 to 5 carbon atoms. The epoxides may be mono- or polyepoxy compounds, i.e. compounds which contain more than one reactive epoxy group. Among others, representative of epoxy compounds are such compounds as ethylene oxide, propylene oxide, 2,3-epoxybutane, 1,2-butyleneoxide, also known as 1,2-epoxybutane, trimethylethylene oxide, tetramethylethylene oxide, butadiene monoxide, styrene oxide, α-methylstyrene oxide, 1,1-diphenylethylene oxide, hexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-chlorophenyl glycidyl ether, methacrylyl chloride epoxide, glycidyl methacrylate, 1,2-epoxy-4-vinylcyclohexane, 2,3-epoxyoctane; 4-butylphenyl glycidyl ether, dipentene monoxide, α-pinene oxide, etc. Preferred epoxides are C₂ -C₅ monoepoxides, such as ethyleneoxide, propyleneoxide, 1,2-butyleneoxide and trimethylethyleneoxide.

In general, the process can be carried out in the presence of any solvent with a high dielectric constant which forms a solution incombination with phenol, sulfur, base and the promoter. As illustrated both by description of this process as well as the process for the preparation of the thiobisphenols described in my copending U.S. patent application Ser. No. 484,995, filed July 1, 1974, now U.S. Pat. No. 3,953,519, issued Apr. 27, 1976, filed concurrently herewith, assigned to the same assignee as this invention, the type of solvent employed in the reaction medium substantially determines the type of phenol, i.e. organomercaptophenol or thiobis(phenol), end product which is formed. In general, in the process of this invention, it is desirable when an organomercaptophenol is desired as the optimum resulting reaction product, in contradistinction to the process described in our aforementioned copending application when thiobisphenols are desired as the optimum resulting reaction product, that the solvent employed be selected from a group consisting of any polar solvent having a high dielectric constant, i.e. a solvent capable of strong hydrogen bonding to the phenol reactant or any intermediates derived therefrom during the course of the reaction. In general, solvents which are useful are solvents commonly referred to as polar aprotic solvents, i.e. solvents that are characterized as solvent species which have the capability of strong hydrogen bonding to solute species and which have high dielectric constants, e.g. dielectric constants or from about 20 to about 50, or even higher.

Among others, suitable solvents in the process of this invention that can be employed are the following:

A. N-methylformamide, N,N-dimethylformamide, acetonitrile, nitrobenzene, γ-butyrolactone, nitromethane, dimethylsulfoxide, sulpholane and N-methylpyrrolidone, etc. and mixtures thereof. Other solvents having high-dielectric constants which dielectric constants can be readily determined by any of the methods well known to those skilled in the art referred to in the publication Solute-Solvent Interactions, J. F. Kotese and K. D. Richey (1969) Marcel Dekker, can be employed in the practice of the invention.

For economic considerations, other solvents can be employed in combination with a high-dielectric constant solvent in this process; however, the use of any non- or lowpolar solvent, such as those noted hereafter, reduces the yield of organomercaptophenol, the reduction in yield directly related to the low dielectric constant of the non-, low- or mediumpolarity solvent.

Representative of non- or low-, or mediumpolar solvents are the following:

B. non- or lowpolar solvents such as hexane, 3-methylpentane, heptane, cyclohexane, methylcyclohexane, cyclohexane, isooctane, p-cymene, cumene, lowpolar decalin, toluene, benzene, diethylether, diphenyl ether, dioxane, thiophene, dimethylsulfide, ethyl acetate, tetrahydroduran, etc., and mixtures thereof; and

C. mediumpolar solvents such as chlorobenzene, anisole, bromobenzene, t-butanol, ethanol, methanol, o-dichlorobenzene, methyl formate, iodobenzene, acetone, acetophenone, etc., and mixtures thereof.

Although not wishing the process of this invention or the scope thereof to be limited by any theory, it is believed that both the rate constants and equilibrium constants associated with the process of this invention are related to (1) the promoter employed, (2) and to the polarity and the dielectric constant of the solvent employed in the preparation of organomercaptophenol. It is also believed that a proton-transfer reaction is involved which transfer rate and equilibrium constant is significantly affected by the solvent both in its initial and transition state. It is further postulated that wherein a high dielectric constant solvent is employed, organomercaptophenols rather than thiobisphenols are the major reaction product because of the ability of the high dielectric constant (hereinafter occasionally referred to by the abbreviation HDC) polar solvents to form strong hydrogen bonds which ability substantially affects the chemical behavior of an essential intermediate species formed within the reaction media in the presence of the phenol, sulfur, base and promoter in the preparation of an organomercaptophenol.

In general, as stated hereinbefore, the process of this invention can be carried out under reaction parameters which broadly comprise contacting a phenol, sulfur, an activated olefin or an epoxy compound, in the presence of a base and a HDC solvent.

The phenol:sulfur mole ratio can vary widely, however, because minimum theoretical stoichiometry requires the reaction of approximately one gram atom of sulfur reaction with one mole of phenol in the preparation of an organomercaptophenol, a minimum mole:gram atom ratio preferably employed is one mole of phenol to one gram atom of sulfur. The reaction can be carried out at any phenyl:sulfur ratio such as ratios within the range of from about 1:0.05 to about 1:20, however, preferably ratios within the range of from about 1:0.5 to about 1:5 and more preferably from about 1:1 to about 1:2 are employed.

Any mole ratio of phenol to base can be employed and can be varied widely. In general, suitable ratios include the use of base in catalytic amounts, e.g. wherein the phenol:base mole ratios are as low as 1:0.001 (0.1 mole % base based on phenol) as well as noncatalytic amounts, e.g. wherein the phenol:base mole ratios are as high as 1:5 (500 mole to base based on phenol) or even higher. In general, satisfactory phenol:base proportions are within the range of from about 1:0.01 to about 1:2, more preferably from about 1:0.02 to about 1:1.5 and even more preferably from about 1:0.1 to about 1:1.2.

The amount of activated olefin or epoxy compound (hereinafter occasionally referred to as thioadditives) which is employed can be varied over a wide range. In general, suitable phenol to thioadditive mole ratios are within the range of from about 1:0.01 to about 1:100, more preferably from about 1:0.5 to about 1:5 and even more preferably from about 1:2 to about 1:4. In order to reduce the opportunity of olefin or epoxy O-alkylation of the hydroxy group of the reactant phenol or resulting organomercaptophenol reaction product preferably the phenol:thioadditive mole proportions are restricted to mole ratios no greater than about 1:3. In a preferred embodiment, it is preferred that the thioadditive be added to the reaction medium in a programmed manner, i.e. in a manner in which continuously regulates the amount of thioadditive admitted to the reaction medium in order to insure that the equilibrium and rate constants of the reaction favor the formation of the organomercaptophenols rather than the O-alkylation of phenyl or organomercaptophenols.

In general, any reaction temperature can be employed wherein the thermal reaction kinetics are not deleterious as to reaction rates, reaction time, yield and/or conversion of the phenol to the desired organomercaptophenol. In general, the reaction temperatures can be varied widely, however, often fall within the range of from about 0° C. to about 200° C., and more often fall within the temperature range of from about 80° C. to about 120° C. The reaction periods also vary widely, however, generally falling within the range of from about 1/2 hour to about 5 hours. The process is preferentially carried out in the presence of an inert atmosphere of nitrogen in order to exclude from the reaction medium any oxygen or oxidizing agents which are well-known to oxidize organic sulfides to sulfoxides or sulfones among other desirable reaction products.

The high dielectric constant solvent can be employed in any amount and can vary widely. In general, the solvent to phenol ratio can be within the range of from about 1000:1 to about 0.05:1 preferably from about 100:1 to about 0.5:1 and even more preferably from about 10:1 to about 1:1. As indicated hereinbefore, in view of the effect of the solvent employed on the major end product, i.e. the organomercaptophenols, obtained by the practice of this invention, as opposed to the major end product, i.e. thiobisphenols, obtained by the practice of my copending invention described in my copending U.S. patent application referred to hereinbefore, Ser. No. 484,995, filed July 1, 1974, now U.S. Pat. No. 4,953,519, issued Apr. 17, 1976, those skilled in the art will readily be able to determine by means of simple experimentation any economic benefits which may be derived from solvent mixtures which include both non-, low- or mediumpolar and high dielectric constant polar solvents.

By the practice of this invention, as described hereinbefore, organomercaptophenols and O-alkylated or ganomercaptophenols can be prepared having the following structural formula: ##STR4## wherein independently each R_(j) and R_(k) is a monovalent substiuent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, each R_(e) and R_(m) is a monovalent substituent selected from the group consisting of hydrogen, hydrocarbon and hydrocarbonoxy radicals, and R_(z) is selected from cyano, carbamoyl, oxycarbonyl, oxyhydrocarbyl, and hydroxy substituted monovalent acyclic and cyclic hydrocarbon radicals, and R is selected from hydrogen and R_(z) radicals.

Preferably, the radicals R_(j) and R_(k) contain from 1 to 30, more preferably from 1 to 15, and even more preferably from 1 to 6 carbon atoms, and the R_(z) radical contains from 2 to 30, more preferably from 2 to 15, and even more preferably from 2 to 6 carbon atoms. The hydrocarbon and hydrocarbonoxy substituents of IV can be the same or different and can be selected from the group consisting of alkyl, cycloalkyl, aryl, alkoxy, cycloalkoxy, aryloxy and combinations thereof.

In order that those skilled in the art may better understand my invention, the following examples are given which are illustrative of the best mode of this invention, however, these examples are not intended to limit the invention in any manner whatsoever. In all of the examples, all parts are by weight unless otherwise stated and the following general procedure was employed. For purposes of brevity, only deviations from this procedure will be set out in the examples.

General Procedure

A solution of phenol, e.g. 2,6-xylenol, and a solvent, e.g. N-methylpyrrolidone is charged to a reaction vessel. Base, sodium hydroxide dissolved in water, is added to the phenol solvent mixture and heated to elevated temperatures, e.g. about 100° C. After removal of the water contained within the reaction medium, the mixture is cooled, e.g. to a temperature of about 70°-80° C. and sulfur, e.g. elemental sulfur (flowers of sulfur) is added to the reaction mixture. The mixture is heated to elevated temperatures, e.g. temperatures of about 80°-120° C., and maintained at elevated temperatures for the duration of the reaction. The promoter is added dropwise during this period. The resulting reaction mixture, generally, is not homogeneous and vigorous stirring is required. The mixture is cooled and diluted if necessary with a suitable diluent, e.g. water, filtered, further diluted with a suitable solvent or solvents in a sequence, e.g. water with a subsequent extraction, e.g. ether. The resulting reaction product mixture is acidified and base-soluble reaction product material, e.g. 4-cyanothioethoxy-2,6-dimethylphenol is removed with ether and washed until neutral. Unreacted phenol, e.g. 2,6-xylenol is removed by distillation. The residue is distilled under high vacuum, analyzed by vapor phase chromatography and a thiophenol as well as any O-alkylated thiophenol is characterized by its melting point in both its crude and purified form, and analytically characterized, based upon a correlation between calculated and found carbon, hydrogen, oxygen, sulfur and nitrogen of the thiobisphenol.

                                      TABLE I                                      __________________________________________________________________________     Summary of Experimental Data - Run Nos. 1-7                                                                                          Mole Ratios              Run                                                                               Reaction Products    Reactants(R), Base(B), Solvent(S),                                                                           Phenol:Sulfur:           No.                                                                               Composition      Yield                                                                              Promoter(P)       Conv.                                                                              Temp.                                                                              Time                                                                               Base:Promoter            __________________________________________________________________________     1. (a) 4-cyanothioethoxy-2,6-dimethyl-                                                             22.8%                                                                             (R) 2,6-xylenol,                                                                            12.2g(0.1m)                                                                          69% 120° C                                                                      3 hrs                                                                              1:2:1:3                     phenol              sulfur,      15.92g(0.3m)                                  Analysis:calc.:63.75C,6.32H,                                                                       (B) sodium hydroxide                                                                        4.0g(0.1m)                                    6.76N,15.44S        (S) N-methylpyrrolidone,                                                                    62ml                                          found:63.2C,6.3H,6.8N,                                                                             toluene,     40ml                                          15.3S               (P) acrylonitrile,                                                                          15.92g(0.3m)                                  (b) 4,4'-dihydroxy-3,3',5,5'-tetra-                                                             1%                                                            methyldiphenyl sulfide                                                      2. (a) 4-(2-hydroxypropylthio)-2,6-                                                                50%                                                                               (R) 2,6-xylenol,                                                                            24.4g(0.2m)                                                                          22% 120° C                                                                      2 hrs                                                                              1:1:1:1                     dimethylphenol      sulfur,      6.4g(0.2m)                                    (b) 4,4'-dihydroxy-3,3',5,5'-tetra-                                                             trace                                                                             (B) sodium hydroxide,                                                                       8.0g(0.2m)                                    methyldiphenyl sulfide                                                                             (S) N-methylpyrrolidone,                                                                    124ml                                                             toluene,     80ml                                                              (P) propyleneoxide,                                                                         11.6g(0.2m)                                3. (a) 4-(2-hydroxypropylthio)-2,6-                                                                25%                                                                               (R) 2,6-xylenol,                                                                            24.4g(0.2m)                                                                          20% 120° C                                                                      22 min                                                                             1:2:1:1                     dimethylphenol      sulfur,      12.8g(0.4m)                                   (b) 4,4'-dihydroxy-3,3',5,5' -tetra-                                                            36%                                                                               (B) sodium hydroxide,                                                                       8.0g(0.2m)                                    methyldiphenyl sulfide                                                                             (S) N-methylpyrrolidone,                                                                    124ml                                                             toluene,     80ml                                                              (P) propyleneoxide,                                                                         11.6g(0.2m)                                4. (a) 4-(2-hydroxypropylthio)-2,6-                                                                24.5%                                                                             (R) 2,6-xylenol,                                                                            12.2g(0.1m)                                                                          93% 120° C                                                                      2 hrs                                                                              1:2.25:0.05:                dimethylphenoxypropanol-2                                                                          sulfur,      7.2g(0.225m)      4.0                         (b) 4,4'-dihydroxy-2,6-dimethyl-                                                                15%                                                                               (B) sodium hydroxide,                                                                       0.2g(0.005m)                                  diphenyl sulfide    (S) N-methylpyrrolidone,                                                                    62ml                                          (c) 4-hydroxy-4'-(2-hydroxypropoxy)-                                                            12.7%                                                                             toluene,     30ml                                          3,3',5,5'-tetramethyldiphenyl                                                                      (P) propyleneoxide,                                                                         23.2g(0.4m)                                   sulfide                                                                        (d) 4,4'-di(2-hydroxypropoxy)-3,3',-                                                            10.8%                                                         5,5'-tetramethyldiphenyl sulfide                                            5. (a) 4,4'-dihydroxy-3,3',5,5'-tetra-                                                             87%                                                                               (R) 2,6-xylenol,                                                                            122.2g(1 m)                                                                          85% 100° C                                                                      4 hrs                                                                              1:1.5:0.05:1                methyldiphenyl sulfide                                                                             sulfur,      48 g(1.5m)                                    (b) 2,6-dimethylphenoxypropanol-2                                                               12%                                                                               (B) metallic sodium,                                                                        1.2g(0.05m)                                   (c) 4-hydroxy-4'-(2-hydroxypropoxy)-                                                            1% (S) --                                                     3,3',5,5'-tetramethyldiphenyl                                                                      (P) propylene oxide,                                                                        58.1g(1.0m)                                   sulfide                                                                     6. (a) 4-cyanothioethoxy-2,6-dimethyl-                                                             34%                                                                               (R) 2,6-xylenol,                                                                            61 g(0.5m)                                                                           69% 120° C                                                                      4 hrs                                                                              1:2:1:3                     phenol              sulfur,      32.1g(1.0m)                                   Analysis:calc.:63.75C,6.32H,                                                                       (B) sodium hydroxide,                                                                       20.0g(0.5m)                                   6.76N,15.44S        (S) N-methylpyrrolidone,                                                                    310ml                                         found:63.2C,6.3H,6.8N,                                                                             toluene,     60ml                                          15.3S               (P) acrylonitrile,                                                                          79.6g(1.5m)                                   (b) 4,4'-dihydroxy-3,3',5,5'-tetra-                                                             1%                                                            methyldiphenyl sulfide                                                      7. (a) 4-(2-carboxyethylthio)-2,6-                                                                 25%,                                                                              (R) 2,6-xylenol,                                                                            61.1g(0.5m)                                                                          40% 120° C                                                                      3 hrs                                                                              1:2:1:3                     dimethylphenol   (11.4g)                                                                           sulfur,      32.1g(1.0m)                                   (b) 2,6-dimethyl-4-mercaptophenol                                                               25.6%,                                                                            (B) sodium hydroxide,                                                                       20 g(0.5m)                                                     (7.9g)                                                                            (S) N-methylpyrrolidone,                                                                    310ml                                                             toluene,     60ml                                                              (P) ethylacrylate,                                                                          150.2g(1.5m)                               __________________________________________________________________________

The organomercaptophenols produced by this process are useful as monomers in the synthesis of esters, carbonates, ethers, epoxy compounds, among may other chemicals synthesized from monohydric phenols. In addition, the organomercaptophenols are also useful as antioxidants.

Several modifications and variations of the invention have been illustrated in the above examples and elsewhere in the disclosure. Accordingly, other modifications and variations will be readily apparent to those skilled in the art in view of applicant's teaching. It is, therefore, to be understood that changes may be made in the particular embodiments of the invention described herein which changes are within the full intended scope of the invention as defined by the appended claims. 

What I claim as new and desire to secure by Letters Patent in the United States is:
 1. A process for the preparation of an organomercaptophenol which comprises the reaction of a member of the class consisting of sulfur, an alkali metal sulfide, an alkaline earth metal sulfide, or an ammonium sulfide, with a phenol of the formula ##STR5## wherein independently each R¹ and R² is a monovalent substituent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, and each R³ and R⁴ is a monovalent substituent selected from the group consisting of hydrogen, hydrocarbon and hydrocarbonoxy radicals, said reaction being carried out in the presence of (1) a base, (2) a member of the class consisting of an activated olefin or an epoxy compound, (3) and a solvent having a dielectric constant greater than about
 20. 2. A process in accordance with claim 1, wherein the activated olefin is of the formula ##STR6## wherein independently at least one of the R_(a), R_(b), R_(c) and R_(d) substituents is selected from the electron-attracting group consisting of cyano, i.e. --CN; carbamoyl, i.e. --CON(R')₂ ; hydrocarbyloxycarbonyl, i.e. --COOR"; oxohydrocarbyl, i.e. --COR", radicals; wherein independently each R' represents hydrogen, acyclic and cyclic hydrocarbon radicals, independently R" represents acyclic and cyclic hydrocarbon radicals.
 3. A process in accordance with claim 1, wherein the epoxy compound is of the formula ##STR7## wherein independently each R_(e) and R_(f) substituents are selected from the group consisting of hydrogen, acyclic and cyclic hydrocarbon radicals.
 4. A process in accordance with claim 1, wherein the mole ratio of phenol to base is from 1:0.001 to 1:5.
 5. A process in accordance with claim 1, wherein the mole ratio of phenol to base is from about 1:0.01 to about 1:2.
 6. A process in accordance with claim 1, wherein the reaction carried out in the temperature range of from about 0° C. to about 200° C.
 7. A process in accordance with claim 6, wherein the temperature is within the range of from about 80° C. to about 120° C.
 8. A process in accordance with claim 1, wherein the organomercaptophenol has the formula ##STR8## wherein independently each R_(j) and R_(k) is a monovalent substituent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, each R_(e) and R_(m) is a monovalent substituent selected from the group consisting of hydrogen, hydrocarbon and hydrocarbonoxy radicals, and R_(z) is selected from cyano-, carbamoyl-, hydrocarbyloxycarbonyl-, oxyhydrocarbyl-, and hydroxy-substituted monovalent acyclic and cyclic hydrocarbon radicals, and R is selected from hydrogen and R_(z) radicals.
 9. A process in accordance with claim 1, wherein the mole ratio of said a phenol to said olefin or epoxy compound is within the range of from about 1:0.01 to about 1:100.
 10. A process in accordance with claim 9, wherein said mole ratio is equal to or less than about 1:3.
 11. A process in accordance with claim 1, wherein the predominant organomercaptophenol is of the formula ##STR9## wherein independently each R_(j) and R_(k) is a monovalent substituent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, each R_(e) and R_(m) is a monovalent substituent selected from the group consisting of hydrocarbon and hydrocarbonoxy radicals, each R_(e) and R_(m) is a monovalent substituent selected from the group consisting of hydrogen, hydrocarbon and hydrocabonoxy radicals, and R_(z) is selected from cyano-, carbamoyl-, hydrocarbyloxycarbonyl-, oxyhydrocarbyl-, and hydroxy-substituted monovalent acyclic and cyclic hydrocarbon radicals, and R is selected from hydrogen and R_(z) radicals. 